Mixed Technology PCB Assembly Capabilities and Equipment Used at ZF
ZF Electronics has several production lines, and each production line is equipped with high-quality production machines and professional workers, which can meet the needs of various types of PCB assembly methods.
Mixed Technology PCB Assembly Services at ZF
We are characterized by one-stop procurement of components, SMT patches, THT plug-ins and finished product assembly and processing to provide the best quality products and services for your electronic product needs.
Different kinds of technology PCB assembly:
Traditional PCB assembly process
1. Application of solder paste
2. Component placement
3. Reflow
4. Check
5. Insert through-hole parts
5. Final inspection and cleaning
Through-Hole Technology Conference (THT):
1. Component placement
The components are installed manually by experienced engineers during PCB manufacturing assembly. The installation process of manually picking and placing components requires maximum precision and speed to ensure component placement. Engineers should follow THT standards and regulations to achieve the best functionality.
2. Inspection and component calibration
The PCB board matches the design transportation frame to ensure the precise placement of the components. If any misallocation of components is found, it will only be corrected at that time. Correction is easier before welding, so the position of the component is corrected at this stage.
3. Wave soldering
In THT, wave soldering is performed to cure the solder paste and keep the component intact at its specific location. In wave soldering, the component-mounted PCB board moves over the slowly moving liquid solder, and the liquid solder is heated at temperatures above 500°F. It is then exposed to a cooler to solidify the connection.
Surface Mount Technology Assembly (SMT):
The PCBA steps followed in SMT assembly are as follows:
1. Application/printing of solder paste
Refer to the design template and apply the solder paste to the board through a solder paste printer. This ensures that the solder paste is printed in a satisfactory quantity at a specific location.
2. Component placement
The placement of components in SMT components is automatic. The circuit board is sent from the printer to the component mounting rack, where the components are picked up and placed by an automatic mechanical pick-and-place mechanism. Compared with manual processes, this electronic assembly fabrication technology saves time and also ensures the accuracy of specific component positions.
3. Reflow soldering
After the components are installed, the PCB is placed in a furnace, and the solder paste is melted and deposited around the components. The PCB passes through the cooler to fix the component in this position.
Surface mount technology (SMT) is more efficient in the complex PCB assembly process.
Due to the increasing complexity of electronic equipment and PCB design, mixed assembly types are also used in the industry. That is, the mixed technology PCB assembly process is a combination of THT and SMT.
Details of Mixed Technology PCB Assembly
PCBA processing and assembly mode mainly depend on the type of surface assembly components, types of installed components, processing equipment conditions and actual production line conditions. PCBA processing can be divided into three types: single-sided mixed loading, double-sided mixed loading and full surface assembly, with a total of six assembly methods.
1. Single side mixed loading
The circuit board used for assembly is a single-sided PCB. Single side hybrid assembly means that the SMT patch and THT plug-in components are mixed on different sides of PCB, the welding surface is a separate side, and the patch surface is another separate side. This kind of assembly method adopts single-sided PCB and wave soldering (now double-wave soldering is generally adopted). There are two specific assembly methods:
(1) First paste and then insert: that is, SMC / SMD is first pasted on surface B (welding surface) of PCB, and then THC is inserted on surface A.
(2) Insert first and then paste: that is, insert THC on the side a of PCB first, and then paste SMD on side B. This kind of assembly is widely used in the assembly of TV sets, radios and other products.
2. Double-sided mixed loading
The circuit board used for assembly is a double-sided PCB. SMT patch and dip plug-in can be mixed and distributed on the same side or both sides of PCB. Double sided hybrid assembly purchase double-sided patch, double wave soldering or reflow soldering. There are also differences between SMC / SMD pasted first and SMC / SMD pasted later in this kind of assembly method. Generally, it is reasonably selected according to the type of SMC / SMD and the size of PCB, and the first paste method is usually used. There are two assembly methods commonly used in this class:
(1) Same plane mode of SMT element and dip element: SMT patch element and dip plug-in element are on the same side of PCB; Dip plug-in components are available on one or both sides. Generally, SMC / SMD is pasted before the plug-in dip.
(2) There are SMT chip components on one and both sides of dip components: put surface assembled integrated chip (SMIC) and tht on side a of PCB, and SMC and small shape transistor (SOT) on side B.
3. Full surface assembly
All circuit boards assembled are single-sided and double-sided PCB (or ceramic substrate). On the PCB, there are only SMT patch components and no tht components. Because the components have not been fully SMT, there are few such assembly forms in practical application. There are two assembly methods for this type: single-sided surface assembly and double-sided surface assembly.
